Almost a year ago, I wrote a post briefly discussing Hawtrey’s 1936 review of the General Theory, originally circulated as a memorandum to Hawtrey’s Treasury colleagues, but included a year later in a volume of Hawtrey’s essays Capital and Employment. My post covered only the initial part of Hawtrey’s review criticizing Keynes’s argument that the rate of interest is a payment for the sacrifice of liquidity, not a reward for postponing consumption – the liquidity-preference theory of the rate of interest. After briefly quoting from Hawtrey’s criticism of Keynes, the post veered off in another direction, discussing the common view of Keynes and Hawtrey that an economy might suffer from high unemployment because the prevailing interest rate might be too high. In the General Theory Keynes theorized that the reason that the interest rate was too high to allow full employment might be that liquidity preference was so intense that the interest rate could not fall below a certain floor (liquidity trap). Hawtrey also believe that unemployment might result from an interest rate that was too high, but Hawtrey maintained that the most likely reason for such a situation was that the monetary authority was committed to an exchange-rate peg that, absent international cooperation, required an interest higher than the rate consistent with full employment. In this post I want to come back and look more closely at Hawtrey’s review of the General Theory and also at Keynes’s response to Hawtrey in a 1937 paper (“Alternative Theories of the Rate of Interest”) and at Hawtrey’s rejoinder to that response.
Keynes’s argument for his liquidity-preference theory of interest was a strange one. It had two parts. First, in contrast to the old orthodox theory, the saving-investment equilibrium is achieved by variations of income, not by variations in the rate of interest. Second – and this is where the strangeness really comes in — the rate of interest has an essential nature or meaning. That essential meaning, according to Keynes, is not a rate of exchange between cash in the present and cash in the future, but the sacrifice of liquidity accepted by a lender in forgoing money in the present in exchange for money in the future. For Keynes the existence of a margin between the liquidity of cash and the rate of interest is the essence of what interest is all about. Although Hawtrey thought that the idea of liquidity preference was an important contribution to monetary theory, he rejected the idea that liquidity preference is the essence of interest. Instead, he viewed liquidity preference as an independent constraint that might prevent the interest rate, determined, in part, by other forces, from falling to a level as low as it might otherwise.
Let’s have a look at Keynes’s argument that liquidity preference is what determines the rate of interest. Keynes begins Chapter 7 of the General Theory with the following statement:
In the previous chapter saving and investment have been so defined that they are necessarily equal in amount, being, for the community as a whole, merely different aspect of the same thing.
Because savings and investment (in the aggregate) are merely different names for the same thing, both equaling the unconsumed portion of total income, Keynes argued that any theory of interest — in particular what Keynes called the classical or orthodox theory of interest — in which the rate of interest is that rate at which savings and investment are equal is futile and circular. How can the rate of interest be said to equilibrate savings and investment, when savings and investment are necessarily equal? The function of the rate of interest, Keynes concluded, must be determined by something other than equilibrating savings and investment.
To find what it is that the rate of interest is equilibrating, Keynes undertook a brilliant analysis of own rates of interest in chapter 13 of the General Theory. Corresponding to every commodity or asset that can be held into the future, there is an own rate of interest which corresponds to the rate at which a unit of the asset can be exchanged today for a unit in the future. The money rate of interest is simply the own rate of interest in terms of money. In equilibrium, the expected net rate of return, including the service flow or the physical yield of the asset, storage costs, and expected appreciation or depreciation, must be equalized. Keynes believed that money, because it provides liquidity services, must be associated with a liquidity premium, and that this liquidity premium implied that the rate of return from holding money (exclusive of its liquidity services) had to be correspondingly less than the expected net rate of return on holding other assets. For some reason, Keynes concluded that it was the liquidity premium that explained why the own rate of interest on real assets had to be positive. The rate of interest, Keynes asserted, was not the reward for foregoing consumption, i.e., carrying an asset forward from the current period to the next period; it is the reward for foregoing liquidity. But that is clearly false. The liquidity premium explains why there is a difference between the rate of return from holding a real asset that provides no liquidity services and the rate of return from holding money. It does not explain what the equilibrium expected net rate of return from holding any asset is what it is. Somehow Keynes missed that obvious distinction.
Equally as puzzling is that Keynes also argued that there is an economic mechanism operating to ensure the equality of savings and investment, just as there is an economic mechanism (namely price adjustment) operating to ensure the equality of aggregate purchases and sales. Just as price adjusts to equilibrate purchases and sales, income adjusts to equilibrate savings and investment.
Keynes argued himself into a corner, and in his review of the General Theory, Hawtrey caught him there and pummeled him.
The identity of saving and investment may be compared to the identity of two sides of an account.
Identity so established does not prove anything. The idea that a tendency for saving and investment so defined to become different has to be counteracted by an expansion or contraction of the total of incomes is an absurdity; such a tendency cannot strain the economic system; it can only strain Keynes’s vocabulary.
Thus, Keynes’s premise that it is income, not the rate of interest, which equilibrates saving and investment was based on a logical misconception. Now to be sure, Keynes was correct in pointing out that variations in income also affect saving and investment. But that just means that income, savings, investment, the demand for money and the supply of money and the rate of interest are simultaneously determined in a macroeconomic model, a model that cannot be partitioned in such a way investment and saving depend exclusively on income and are completely independent of the rate of interest. Whatever the shortcomings of the Hicksian IS-LM model, it at least recognized that the variables in the model are simultaneously, not sequentially, determined. That Keynes, who was a highly competent and skilled mathematician, author of one of the most important works ever written on probability theory, seems to have been oblivious to this simple distinction is hugely perplexing.
In 1937, a year after publishing the General Theory, Keynes wrote an article “Alternative Theories of the Rate of Interest” in which he defended his liquidity-preference theory of interest against the alternative theories of interest of Ohlin, Robertson, and Hawtrey in which the rate of interest was conceived as the price of credit. Responding to Hawtrey’s criticism of his attempt to define aggregate investment and aggregate savings as different aspects of the same thing while also using their equality as an equilibrium condition that determines what the equilibrium level of income is, Keynes returned again to a comparison between the identity of investment and savings and the identity of purchases and sales:
Aggregate saving and aggregate investment . . . are necessarily equal in the same way in which the aggregate purchases of anything on the market are equal to the aggregate sales. But this does not mean that “buying” and “selling” are identical terms, and that the laws of supply and demand are meaningless.
Keynes went on to explain the relationship between his view that saving and investment are equilibrated by income and his view of what determines the rate of interest.
[T]he . . . novelty lies in my maintaining that it is not the rate of interest, but the level of incomes which ensures equality between saving and investment. The arguments which lead up to this initial conclusion are independent of my subsequent theory of the rate of interest, and in fact I reached it before I had reached the latter theory. But the result of it was to leave the rate of interest in the air. If the rate of interest in not determined by saving and investment in the same way in which price is determined by supply and demand, how is it determined? One naturally began by supposing that the rate of interest must be determined in some sense by productivity – that it was, perhaps, simply the monetary equivalent of the marginal efficiency of capital, the latter being independently fixed by physical and technical considerations in conjunction with expected demand. It was only when this line of approach led repeatedly to what seemed to be circular reasoning, that I hit on what I now think to be the true explanation. The resulting theory, whether right or wrong, is exceedingly simply – namely, that the rate of interest on a loan of given quality and maturity has to be established at the level which, in the opinion of those who have the opportunity of choice – i.e., of wealth-holders – equalises the attractions of holding idle cash and of holding the loan. It would be true to say that this by itself does not carry us very far. But it gives us firm and intelligible ground from which to proceed.
The concluding sentence seems to convey some intuition on Keynes’s part of how inadequate his liquidity-preference theory is as a theory of the rate of interest. But if he had thought the matter through to the bottom, he could not have claimed even that much for it.
Here is Hawtrey’s response to Keynes’s attempt to defend his position.
The part of Mr. Keynes’ article . . . which refers to my book Capital and Employment is concerned mainly with questions of terminology. He finds fault with my statement that he has defined saving and investment as “two different names for the same thing.” He himself describes them as being “for the community as a whole, merely different aspects of the same thing ” . . . . If, as I suppose, we both mean the same thing by the same thing, the distinction is rather a fine one. In Capital and Employment . . . I point out that the identity of . . . saving and investment . . . “is not a purely verbal proposition: it is an arithmetical identity, comparable to two sides of an account.”
Something very like that seems to be in Mr. Keynes’ mind when he compares the relation between saving and investment to that between purchases and sales. Purchases and sales are necessarily equal, but “this does not mean that buying and selling are identical terms, and that the laws of supply and demand are meaningless.”
Purchases and sales are also “different aspects of the same thing.” And surely, if demand were defined to mean purchases and supply to mean sales, any proposition about economic forces tending to make demand and supply equal, or about their equality being a condition of equilibrium, or indeed a condition of anything whatever, would be nonsense.
“The theory of the rate of interest which prevailed before 1914,” Mr. Keynes writes, “regarded it as the factor which ensured equality between saving and investment,” and he claims therefore that, “in maintaining the equality of saving and investment,” he is “returning to old-fashioned orthodoxy.” That is not so. Old-fashioned orthodoxy never held that saving and investment could not be unequal; it held that their inequality, when it did occur, was inconsistent with equilibrium. If they are defined as “different aspects of the same thing,” how can it possibly be “the level of incomes which ensures equality between saving and investment”? Whatever the level of incomes may be, and however great the disequilibrium, the condition that saving and investment must be equal is always identically satisfied.
While it is widely recognized that Hawtrey showed that Keynes’s attempt to define investment and savings as different aspects of the same thing and as a condition of equilibrium was untenable (a criticism made by others like Haberler and Robertson as well), the fallacy committed by Keynes was not a fatal one, though the fallacy has not been entirely extirpated from textbook expositions of the basic Keynesian model. Unfortunately, the related fallacy underlying Keynes’s attempt to transform his liquidity-preference theory of the demand for money into a full-fledged theory of the rate of interest was not as easily exposed. In his review, Hawtrey discussed various limitations of Keynes’s own-rate analysis, but, unless I have missed it, he failed to see the fallacy in supposing that liquidity premium on money explains the equilibrium net return from holding assets, which is what the real (or natural) rate of interest corresponds to in the analytical framework of chapter 13 of the General Theory.